From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6775DC4332E for ; Thu, 19 Mar 2020 13:38:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 331D920787 for ; Thu, 19 Mar 2020 13:38:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584625095; bh=mEhCeYo5+LyTd6CUmygiuKW71GgnuF7c5fWXGTZcf60=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=akKp5Mf/ZXr5Mba+j7Pgn9ZsinyjB9OI+7NfxOnlEVqiNPJs22ex+kB0d8O1Jm3Hm uQvZTkkHNNHlSr3NqnICLaDb09sJx/1Lnu+ocp/8CKabY7LYvYe9GnKHrqJtpCefNB 6uFZ4AgsvMDCwB9utxYAmXa8BPl1JPPQd2hAUS3o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727860AbgCSNHM (ORCPT ); Thu, 19 Mar 2020 09:07:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:50648 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727843AbgCSNHH (ORCPT ); Thu, 19 Mar 2020 09:07:07 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8CC4120757; Thu, 19 Mar 2020 13:07:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584623227; bh=mEhCeYo5+LyTd6CUmygiuKW71GgnuF7c5fWXGTZcf60=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jxJ/B30IWwFJ/+1ZK4i0MHui+bnFzAfznoaN2b5HJZqR9ecN2NadjWRd1RCkagREE takREfTGHSJyhB2a4+uVipKFqvYB0U79u8NfJDLrlAZ6AkhkhwXoelazMd/wOJddj8 3EKuqQYbK0HF4CQRkfdvIBoBXwt8V1HFHJpCf+dQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Sven Eckelmann , Marek Lindner , "David S. Miller" Subject: [PATCH 4.4 51/93] batman-adv: Fix ICMP RR ethernet access after skb_linearize Date: Thu, 19 Mar 2020 13:59:55 +0100 Message-Id: <20200319123941.177718976@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200319123924.795019515@linuxfoundation.org> References: <20200319123924.795019515@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sven Eckelmann commit 3b55e4422087f9f7b241031d758a0c65584e4297 upstream. The skb_linearize may reallocate the skb. This makes the calculated pointer for ethhdr invalid. But it the pointer is used later to fill in the RR field of the batadv_icmp_packet_rr packet. Instead re-evaluate eth_hdr after the skb_linearize+skb_cow to fix the pointer and avoid the invalid read. Fixes: da6b8c20a5b8 ("batman-adv: generalize batman-adv icmp packet handling") Signed-off-by: Sven Eckelmann Signed-off-by: Marek Lindner Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/routing.c | 1 + 1 file changed, 1 insertion(+) --- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -359,6 +359,7 @@ int batadv_recv_icmp_packet(struct sk_bu if (skb_cow(skb, ETH_HLEN) < 0) goto out; + ethhdr = eth_hdr(skb); icmph = (struct batadv_icmp_header *)skb->data; icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph; if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)